Pitot probes are commonly used on aircraft and other applications for measuring airspeed. In certain weather conditions, a water droplet(s) can plug up the air pressure orifice at the front of the pitot probe, causing the pitot probe to incorrectly read the airspeed. In the past, this problem has been solved by using a heated pitot probe which uses heat to vaporize the water droplet(s). The heat is either generated electrically, or by diverting heat from the aircraft's engine(s). Other ways this problem has been solved is by using a specially calibrated pitot probe with a drain hole to remove water droplet(s) from the probe while installed, or by creating a pitot probe with a large diameter to prevent water droplet(s) from plugging up the probe.
Many small aircraft, including unmanned aerial vehicles (UAV's), typically cannot afford to carry the weight and size of previous pitot probes such as the probes listed above, and may not have sufficient energy resources to spare energy for use by a heated probe.